Question

我无法将控制台输出重定向到Windows窗体文本框。问题与线程有关。我正在以下列方式运行控制台应用程序，

private void RunConsoleApp()
{
    Process proc = new Process();
    proc.StartInfo.FileName = "app.exe";
    proc.StartInfo.Arguments = "-a -b -c";
    proc.StartInfo.UseShellExecute = false;

    // set up output redirection
    proc.StartInfo.RedirectStandardOutput = true;
    proc.StartInfo.RedirectStandardError = true;    
    proc.EnableRaisingEvents = true;
    proc.StartInfo.CreateNoWindow = true;

    // Set the data received handlers
    proc.ErrorDataReceived += proc_DataReceived;
    proc.OutputDataReceived += proc_DataReceived;

    proc.Start();
    proc.BeginErrorReadLine();
    proc.BeginOutputReadLine();
    proc.WaitForExit();

    if (proc.ExitCode == 0)
    {
        out_txtbx.AppendText("Success." + Environment.NewLine);
    }
    else
    {
        out_txtbx.AppendText("Failed." + Environment.NewLine);
    }
}

然后使用此输出处理程序

捕获和处理数据

// Handle the date received by the console process
void proc_DataReceived(object sender, DataReceivedEventArgs e)
{
    if (e.Data != null)
    {
        if ((e.Data.EndsWith("DONE.")) || (e.Data.EndsWith("FAILED.")) ||
            (e.Data.StartsWith("RESET")))
        {
            // This crashes the application, but is supposedly the correct method
            this.AppendText(e.Data + Environment.NewLine);

            // This works, but the debugger keeps warning me that the call
            // is not thread safe
            //out_txtbx.AppendText(e.Data + Environment.NewLine);
        }
    }
}

然后按照这样附加控制台文本，

delegate void AppendTextDelegate(string text);

// Thread-safe method of appending text to the console box
private void AppendText(string text)
{
    // Use a delegate if called from a different thread,
    // else just append the text directly
    if (this.out_txtbx.InvokeRequired)
    {
        // Application crashes when this line is executed
        out_txtbx.Invoke(new AppendTextDelegate(this.AppendText), new object[] { text });
    }
    else
    {
        this.out_txtbx.AppendText(text);
    }
}

在我看到的所有文档和示例中，这似乎是正确的方法，除了它在调用out_txtbx.Invoke时崩溃应用程序。

有什么可以打破以及有什么替代方法可以做到这一点？

解决方案（正如Hans Passant所指出的那样）

问题是该应用程序由于该行而陷入“致命的拥抱”，

proc.WaitForExit();

应删除该行，方法应如下所示，

private void RunConsoleApp()
{
    Process proc = new Process();
    proc.StartInfo.FileName = "app.exe";
    proc.StartInfo.Arguments = "-a -b -c";
    proc.StartInfo.UseShellExecute = false;

    // set up output redirection
    proc.StartInfo.RedirectStandardOutput = true;
    proc.StartInfo.RedirectStandardError = true;    
    proc.EnableRaisingEvents = true;
    proc.StartInfo.CreateNoWindow = true;

    // Set the data received handlers
    proc.ErrorDataReceived += proc_DataReceived;
    proc.OutputDataReceived += proc_DataReceived;

    // Configure the process exited event
    proc.Exited += new EventHandler(ProcExited);

    proc.Start();
    proc.BeginErrorReadLine();
    proc.BeginOutputReadLine();

    // This blocks the main thread and results in "deadly embrace"
    // The Process.Exited event should be used to avoid this.
    //proc.WaitForExit();
}

并且应该提供事件处理程序，

/// <summary>
/// Actions to take when console process completes
/// </summary>
private void ProcExited(object sender, System.EventArgs e)
{
    Process proc = (Process)sender;

    // Wait a short while to allow all console output to be processed and appended
    // before appending the success/fail message.
    Thread.Sleep(40);

    if (proc.ExitCode == 0)
    {
        this.AppendText("Success." + Environment.NewLine);
        ExitBootloader();
    }
    else
    {
        this.AppendText("Failed." + Environment.NewLine);
    }

    proc.Close();
}

Answer 1

proc.WaitForExit();

它被称为死锁。您的主线程被阻止，等待进程退出。这使它无法承担基本职责。就像保持UI更新一样。并确保调度Control.Invoke（）请求。这会阻止AppendText（）方法完成。这会停止退出的过程。这会阻止你的UI线程通过WaitForExit（）调用。 “致命的拥抱”，又名死锁。

您无法阻止主线程。请改用Process.Exited事件。

Answer 2

尝试

out_txtbx.Invoke(new AppendTextDelegate(this.AppendText), text);

如何以线程安全的方式将控制台程序的输出重定向到文本框？

2 个答案: